1. Introduction

Not sure which IO needle to use? You’re not the only one. IO (intraosseous) access is used in emergencies when IV is hard to get. But there are different needle sizes—pink, blue, and yellow—and it can be confusing to choose the right one.

In this article, we will explain:

• What each color means
• Which size fits which patient
• How to choose the right IO needle quickly

Let’s make it simple.

2. What is an IO Needle Made Of?

All IO needles have a few basic parts:

• Needle shaft – The long part that enters the bone
• Stylet – A stiff inner rod that helps with insertion
• Color-coded hub – Shows the needle size
• Luer lock connector – Attaches to syringes or IV tubing

Most IO systems, like the EZ-IO, use a power drill to insert the needle quickly and safely.

3. IO Needle Sizes and Color Codes

IO needles come in three standard sizes, each with a different color. Here's what each one means:

• Pink is short and only used for very small infants.
• Blue is the most common size—great for most patients.
• Yellow is long and works for patients with more soft tissue.

Tip: If you're unsure, start with the blue needle. If it’s too short or sinks into soft tissue, switch to yellow.

4. How to Choose the Right IO Needle?

Here’s a quick way to decide:

4.1 Based on patient size:

• Small baby? → Pink (15 mm)
• Child or average adult? → Blue (25 mm)
• Larger adult or lots of tissue at the site? → Yellow (45 mm)

4.2 Based on insertion site:

• Proximal tibia → Blue for most, Pink for infants
• Proximal humerus → Often needs Yellow
• Sternum (if allowed) → Use Yellow with special IO kits

4.3 Check placement:

• You should feel a “pop” as the needle enters the bone
• The hub should sit close to the skin
• You should be able to flush saline easily (no resistance)

5. Common Questions & Tips (FAQs)

1. What if the needle doesn’t reach the bone?

Use a longer one (switch from blue to yellow).

2: What if the needle is too loose or wobbly?

You may have gone too shallow—try reinserting at the right angle.

3: Can I reuse the same needle if I fail?

No. IO needles are single-use only.

4: What happens if I use the wrong size?

You may get poor flow, fluid leakage, or failed access. Always choose based on the site and body size.

5: What gauge needle is used for intraosseous injection?

Most IO needles are 15-gauge, regardless of their length. The gauge stays the same; only the length changes based on the patient.

6: How do you know if an IO needle is inserted correctly?

Here’s what to check:

• You feel a clear “pop” as the needle enters the bone marrow
• The needle hub sits close to the skin, not buried or floating
• You can aspirate bone marrow or flush saline easily with no resistance
• The site stays dry (no swelling or leakage)

6. Conclusion

Choosing the right IO needle size is simple—once you understand the color system.

• Pink = Small infants
• Blue = Most patients
• Yellow = Adults with more tissue

In emergencies, confidence matters. Knowing your IO needle sizes helps you work faster and safer. Practice with IO trainers, review your color codes, and keep it simple when it counts.